



Although there have been numerous previous demonstrations that toxin can be fo 
within duck carcasses on mud flats, data from the Bear River work revealed that syst 
atic removal of carcasses from an area stricken by outbreaks of botulism was not 
measurably effective in reducing subsequent mortality on that area. 
Studies of avian' botulism aré being continued by the Fish and Wildlife Service 
through its Denver Wildlife Research Laboratory, with the cooperation of the United 
States Public Health Service, through its Microbiological Institute, Rocky Mountain 
Laboratory, Hamilton, Mont. Joint reports by the Fish and Wildlife Service and the 
Public Health Service aré available in limited quantities to agencies or individuals 
actively interested in the subject. 
NATURE OF. DISEASE AND FACTORS IN ITS INCIDENCE 
It has been shown that botulism is not the result of an infection in whith bacte 
invade the tissues of thé host organism. Instead it involves intoxication resulting 
from the absorption of products of metabolism of bacterial cells (Clostridium botuli 
type C). The toxin of Clostridium botulinum, type A -- and presumably that of type C 
also -- is a protein. Tt is further thought to be a particular type of protein termed 
a globulin. The molecular weight of this complex compound has been calculated to be 
between 1,000,000 and 2,000,000 (Lamanna, McElroy, and Eklund, 1946) while by comparis 
that of the simple molecule of water is 18. 
Coburn (1942) concluded that the toxin of type C consisted of at least two frac- 
tions, though he believed it probable that they seldom, if ever, occurred separately 
under natural conditions. He found that one of these, fraction A, was toxic by mouth, 
thermostable, nonantigenic, nonneutralizable by type C antitoxin, stable at room temps 
atures, stable to bacterial action, destroyed by strongly alkaline solutions, and 
volatile upon boiling. Fraction B is reportedly nontoxic when taken by mouth in the 
absence of fraction A, but is toxic when injected into the peritoneal cavity. Upon t 
restoration of fraction A, the toxicity by the oral route was said to return. Fractig 
Ais a rapidly acting neurotoxin. Fraction B has the character of more usual bacteri 
toxinse It is likewise a neurotoxin. 
The bacteria (Clostridium botulinum, type C) which form this toxin belong to a 
taxonomic grouping with special characteristics. They are saprophytes, anaerobes, and 
spore~formers. As such, they apparently are almost everywhere. They have been found 
in every duck-sickness location where an effective search has.been made, as well as in 
other locations in the western United States, where epizootics of avian botulism have 
not occurred. -Microscopic spores formed by these bacteria have such resistance to 
climatic conditions that long periods of the most adverse weather do not destroy then. 
The spores are resistant to boiling for hours (Jordan and Burrows). Under favorable 
growth conditions a considerable population of vegetative forms of ‘the bacteria can 
rapidly be established. 
EPTZOOLOGY 
_ Numerous investigations of the past have disclosed a series of factors or condi- 
tions usually associated with outbreaks of waterfowl botulism. Not all of the typical 
conditions outlined are fulfilled in every instance of botulism, but on the other hand 
no major occurrence of the disease has failed to conform to many (or most) of the 
factors outlined belows 
b= 
